We are developing epithelial cell lines obtained from C3H mouse ventral prostates and characterizing them with respect to their growth properties, ultrastructure, and androgen, estrogen, and progestin receptors. These cells will be treated with chemical carcinogens in order to obtain oncogenic transformation. The transformed cells will be similarly characterized. The techniques developed will be applied to the development of similar cell lines from normal human prostate and benign hypertrophic prostate. A series of transplantable rat prostate tumors are being maintained in vivo and cultured. The status of their androgen and estrogen receptors will be compared with their growth characteristics in vivo.